Fuel systems



y 4, 966 E. A. JOHNSON ET AL 3,252,424

FUEL SYSTEMS Filed Jan. 15, 1960 4 Sheets-Sheet l r INVENTORS j L I ELDON A. JOHNSON I N EDWARD M. MA ON AGENT May 24, 1966 E. A. JOHNSON ET AL FUEL SYSTEMS 4 Sheets-Sheet 2 Filed Jan. 15, 1960 FIG.3.

INVENTORS ELDON A. JOHNSON EDWARD M. MASON AGENT y 1966 E. A. JOHNSON ET AL FUEL SYS TEMS 4 Sheets-Sheet 5 Filed Jan. 15, 1960 INVENTORS ELDON A. JOHNSON EDWARD M. MASON AGENT I 7 r, 7 4' 4 57 m 6 w w 9 3 9 m 9 9 M l/W m 0 m u m Q I l4 1/ \f m 5 |ll|si I 7 H H B M T 5 T1 Z 5 1l 0 u Q l w m 6 G 9 V I z W 7 l w 5 W, F 2 m 1M 7 9 we y 1966 E. A. JOHNSON E A FUEL SYSTEMS 4 Sheets-Sheet 4 Filed Jan. 15. 1960 INVENTOR.

AGENT United States Patent 3,252,424 FUEL SYSTEMS Eldon A. Johnson, Sunset Hills, and Edward M. Mason,

St. .Iohns, Mo, assignors to AF Industries, Incorporated, New York, N.Y., a corporation of New Jersey Filed Jan. 15, 1960, Ser. No. 2,656 4 Claims. (6!. 10315il) This invention relates to fuel systems for internal combustion engines, more particularly to fuel systems for automotive engines, and to fuel pumps used in such systems.

The invention pertains to a fuel system of the type wherein fuel is supplied from the fuel tank of the automotive vehicle to a carburetor having a fuel bowl from which fuel overflows above a predetermined level, overflow fuel being returned to the tank, there being a constant circulation of fuel from the tank to the carburetor and back to the tank when the engine is in operation. This type of fuel system may be referred to as a recirculating system, since fuel is constantly being recirculated through the system when the engine is in operation. In such a system, fuel needs to be pumped from the tank to the fuel bowl at a rate in excess of the engine fuel demand in order to maintain the predetermined level or head of fuel in the bowl for accurate metering of fuel from the bowl to the engine, and overflow fuel needs to be pumped back to the tank to avoid flooding. The pumping of overflow fuel back to the tank is referred to as scavenging. r

A more conventional fuel system for the engine of an automatic vehicle comprises a float-type carburetor and an engine-driven pump for pumping fuel from the fuel tank of the vehicle to the fuel bowl of the carburetor, admission of fuel to the bowl being controlled by a float valve. Such a pump conventionally comprises a diaphragm, a compression spring tending to move the diaphragm in one direction through a dischargestroke, a diaphragm-actuating rod for moving the diaphragm in the opposite direction, a rocker arm for moving the diaphragm-actuating rod, and a push rod actuated by an engine-driven cam for operating the rocker arm. The rocker arm is provided to avoid any necessity for using packing to make a fuel-tight seal on the diaphragm-actuating rod. In this respect, it will be understood that rod packing exposed to fuel is apt to cause trouble, due, for example to swelling of the packing and binding on the rod.

The invention comprehends the provision of an improved packless diaphragm pump construction, i.e., a pump construction devoid of such packing for the diaphragm-actuating rod as might fail under the attack of fuel, which enables the provision of a practical, economical dual diaphragm pump for a recirculating sy tem by means of which the pumping of fuel to the fuel bowl of the carburetor and the scavagening of fuel from the carburetor is accomplished by means. of a single diaphragm, with the diaphragm spring-loaded for movement in one direction through a primary discharge stroke and a scavenger intake stroke, and adapted to be moved in the opposite direction through a primary intake stroke and a scavenger discharge stroke by driving the diaphragm-actuating rod from the engine, and which also enables the provision of a practical, economical packless diaphragm pump for a conventional float carburetor system wherein the diaphragm-actuating rod may be directly driven by a camoperated push rod in line with the diaphragm-actuating rod without the interposition of a rocker arm.

The pump construction of this invention which is applicable to both the dual diaphragm pump and the pump for a conventional float carburetor system essentially cornprises a pump body having an opening, a diaphragm having a hole therein registering with the opening in the body, the diaphragm having its inner margin around the hole therein and its outer margin sealed to the body with an intermediate annular portion of the diaphragm free for flexure, thereby providing a pump chamber on one side of the diaphragm. A head is secured in sealed relation to the intermediate annular portion of the diaphragm on the other side of the diaphragm, there being an air space between the head and the diaphragm which is vented to the outside of the body. A diaphragm-actuating rod extends through the opening in the body and the hole in the diaphragm and engages the head. With this arrangement, a spring may be used biasing the head in the direction toward the rod and thereby tending to contract the pump chamber. With the inner margin of the diaphragm around the hole therein sealed to the body, no packing is required on the rod to seal the pump chamber. In the case of the dual pump of this invention, there is an additional pump chamber on the other side of the diaphragm.

As regards the dual diaphragm pump and the recirculating system including the pump, this invention involves an improvement over the pump and system disclosed and claimed in the copending coassigned application of Eldon A. Johnson, Serial No. 2,660, filed January 15, 1960, entitled Fuel Systems.

In this respect, it will be observed that where in the stated copending application, the primary and scavenger pump chambers are simultaneously spring-discharged, in the present invention only the primary pump chamber is spring-discharged, the discharge of the scavenger pump chamber being accomplished by the engine-driven cam. Thus, the load on the spring may be less in the present case than in the prior case.

Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

FIG. 1 is a view in elevation illustrating a dual diaphragm pump of this invention in use on the engine of an automotive vehicle in a recirculating fuel system of this invention;

FIG. 2 is a vertical section of the dual diaphragm pump taken essentially on line 2--2 of FIG. 3;

FIG. 3 is a top plan view of the dual diaphragm pump, with pants broken away and shown in section;

FIG. 4 is a bottom plan view of the dual diaphragm pump, with parts broken away and shown in section;

FIG. 5 is a fragment of FIG. 2 showing a moved position of parts;

FIG. 6 is a vertical transverse section taken on line 6-6 of FIG. 2;

FIG. 7 is a view in elevation illustrating a single-acting pump of this invention in use on the engine of an automotive vehicle in 1a float carburetor fuel system;

FIG. 8 is a vertical section of the single-acting pump; and

FIG. 9 is a section taken on line 99 of FIG. 8.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawmgs.

Referring to FIG. 1 of the drawings, there is indicated at ?l the frame of an automotive vehicle having engine 3 at the front. The engine is adapted. to be supplied with fuel from fuel tank 5 at the rear of the vehicle by a recirculating fuel system S of this invention which includes pump P of this invention and carburetor C mounted on the engine. Pump P is mounted on the side of the engine. Carburetor C is mounted on intake manifold 7 on top of the engine. An air filter for carburetor C is indicated at 9. The exhaust manifold of the engine is indicated at 11.

Carburetor C is a floa-tless carburetor having a fuel bowl and an overflow chamber, fuel spilling over into the overflow chamber from the bowl on exceeding a predetermined level in the bowl. Reference may be made to the above-noted copending coassigned Johnson application for details of a fiatless carburetor which may be used.

Pump P is -a dual diaphragm pump having a lower pump section 17 (which in recirculating system S is the primary pump section) having an inlet nipple at 19 (see FIGS. 2 and 4) to which is connected a fuel supply line 21 (see FIG. 1) from fuel tank and an outlet nipple at 23 (see FIG. 4) to which is connected a fuel delivery line 25 (see FIG. 1) leading to the fuel bowl of carburetor C. Pump P also has an upper pump section 27 (which in recirculating system S is the scavenger pump section) having an inlet nipple at 29 (see FIGS. 2 and 3) to which is connected a fuel line 31 (see FIG. 1) for overflow from the carburetor C and an outlet nipple at 33 (see FIG. 3) to which is connected a fuel return line 35 (see FIG. 1) leading back to the tank 5. As shown in FIG. 1, an electric pump 37 may be provided in tank 5 for pumping fuel from the tank through line 21 to the lower pump section 17. This is optional.

Pump P comprises a rocker arm housing 41 which is open at one end (its right end as appears in FIG. 2), this end being referred to as the inner end of the housing. The housing is of generally rectangular form in vertical cross section of decreasing height from its inner end to its outer end (which is closed). At its inner end it has a flange 43 for attaching it to the engine 3 in communication with the crankcase of the engine. A rocker arm 47 is pivoted at 49 in the housing 41 for rocking motion on a horizontal axis transverse to the housing. Arm 47 has a downwardly extending end portion 51 which projects out of the open inner end of the housing. A leaf spring 53 is secured as by a rivet at 55 to the arm extending down on the outside of end portion 51 of the arm. When the pump 15 is mounted on the engine, the free end portion of leaf spring 53 is engaged by a push rod 57 actuated by an engine-driven cam 59. This cam is adapted to rock the arm clockwise through a cam-powered stroke away from its FIG. 2 position. The arm is adapted to be returned counter clockwise back to its FIG. 2 position by a spring to be described.

The rocker arm housing 41 is integrally formed at its outer end with an essentially cup-shaped pump body 61 having a circular bottom 63 (see FIGS. 4 and 6) and an upstanding annular wall 65 which is of cylindrical form on the outside and of conical form on the inside. The interior conical surface of wall 65 is designated 67. It diverges (flares outward) in the direction away from the bottom of the cup, the angle of flare being about 56, for example. At the center of the bottom of the cup-shaped pump body 61 is an upstanding cylindrical hub 69 integrally formed on the outer end of rocker arm housing. Hub 69 has a vertical bore or opening 71 as shown in FIG. 2 extending upward from the outer end of the housing 41 to a counterbore 73 in its upper end. The upper end portion of the hub 69 is exteriorly tapered, thereby providing an exterior conical surface 75 which converges in the direction away from the bottom 63 of the cupshaped body 61. The upper end of the hub is approximately at the same level as the rim of the cup-shaped body 61.

Extending down from the bottom 63 of the cup-shaped primary pump body 61 at opposite sides of the hub 69 are two bosses 75 and 77 which are cored to provide cylindrical recesses 79 and 81 extending down from the interior of body 61 and open at their upper ends to the interior of body 61. Below the recess 79 is a lower pump inlet passage 83. This is the primary inlet passage as the pump is used in a recirculating system S. Inlet nipple 19 extends into this passage. Extending tangentially from recess 81 is a lower pump outlet passage 87. This is the primary outlet passage as the pump is used in recirculating system S. Outlet nipple 23 extends from this passage. Recess 79 contains an inlet check valve 91; recess 81 contains an outlet check valve 93.

The cup-shaped pump body 61 is closed by an annular diaphragm 95 consisting of a relatively thin disk of flexible fuel-resistant material, such as a suitable synthetic rubber, which, in unstressed condition, is flat or at least substantially flat. The diaphragm has a center hole 97 the diameter of which, when the diaphragm is flat, may be slightly smaller than the diameter of the upper end of the conical tip 75 of the hub 69. The outside diameter of the diaphragm, in its flat condition, is greater than the outside diameter of the annular wall of the body 61. The diaphragm is secured as by rivets 99 to a hat-shaped sheet metal member 101 which constitutes a head on the diaphragm. This head 101 has an outwardly extending annular flat bottom flange 105 with a turnedup peripheral lip 107. Head 101 is large enough to fit over the upper end of hub 69. An intermediate annular portion of the diaphragm is compressed between the flange 105 on the head 101 and a washer 109, rivets 99 extending through rivet holes in the flange 105, the diaphragm and the washer, so as to provide a fluid-tight seal between the diaphragm and the flange 105. An air chamber 111 is thereby defined between the head 101 and the diaphragm. The internal diameter of the washer 109 is greater than the diameter of the hub 69, corresponding essentially to the internal diameter of the lower part of the head 101. The head 101 has an upwardly extending central hollow projection at the top providing a downwardly opening socket 115.

The diaphragm is applied to the cup-shaped body 61 With the center hole 97 in the diaphragm registering with the counterbored openings 73 the hub 69 of body 61, and with the central portion or inner margin of the diaphragm around the center hole 97 therein distorted to conical form and engaging the conical surface at the upper end of the hub 69 and the outer peripheral marginal portion of the diaphragm distorted to conical form and engaging the interior conical surface 67 of the wall 65 of the cup-shaped body 61, with head 101 on the outside and washer 109 on the inside as regards body 61. The inner margin of the diaphragm is clammd against conical surface 75 in fluid-tight sealing engagement therewith by a tubular clamp element or thimble 119 extending through the center hole 97 in the diaphragm and pressed into the counterbored opening 73 in the hub 69 and having an external annular conical head 121 at its upper end engaging the inner margin of the diaphragm. The outer margin of the diaphragm is clamped against the conical surface 67 in fluid-tight sealing engagement therewith by a casting 123 which constitutes the body of the pump section 27 and which serves as an enclosure on body 61 for the hat-shaped or cup-shaped head 101 and the diaphragm.

The diaphragm 95, initially assembled as above described between the lower pump body 61 and the upper pump body 123, assumes the form of an annular downwardly directed loop with a flat bottom portion and coni-- cal inner and outer side portions which diverge from the fiat bottom portion in upward direction (see FIGS. 2 and 6). The upper margin of the inner side portion of the annular loop is clamped against the conical upper end of the hub 69 by thimble 119 and the upper margin of the outer side portion of the annular loop is clamped against conical surface 67 by the upper pump body 123. The inner side portion of the annular loop lies on the conical upper end of the hub; the outer side portion lies on conical surface 67. The intermediate annular E I i of the diaphragm attached to the flange 105 of head 101 is slack and free for flexure. The top of the head 101 engages the upper end of the thimble 119 and washer 109 is contiguous to the bottom of the cup-shaped body 61. The diaphragm, being sealed to the cup-shaped primary pump body 61 at the inner margin of the diaphragm around the center hole 97 in the diaphragm and at the outer margin of the diaphragm, closes off an annular space in body 61 around the hub 69, this space constituting an annular lower pump chamber 125. This is the primary pump chamber as the pump is used in recirculating fuel system S.

The bottom of the thimble 119 has a central hole 126 accommodating a diaphragm-actuating rod 127.. This rod is vertically slidable in the hub 69, having a sliding fit in the bore 71 in the hub. A wiper for wiping crankcase oil from the rod is indicated at 129 in the lower end of the counterbore 73 in the boss. Wiper 129 comprises a ring of flexible fuel-resistant material such as a suitable synthetic rubber having an inturned conical lip which hugs the .rod. It is held in the lower end of the counterbore 73 by a sheet metal ring 131 press-fitted in the counterbore prior to pressing thimble 119 therein. The bottom of thimble 119 is spaced above the ring 131, and hub 69 is provided with a breather passage or vent 133 open at its inner end to the space between the bottom of thirnble 119 and the ring 131 and open at its outer end to the atmosphere outside of the cup-shaped body 61. The lower end of the rod 127 engages the inner end of the rocker arm 47. The rod 127 has a reducedd-iameter upper end extension 135 received in socket 115 at the top of the head 191. A collar 137 is applied to the annular shoulder on rod 127 at the lower end of extension 135 engaging the inside of the top of the head 101.

The body 123 of the upper pump section 27 is of circular form in plan, having a downwardly opening circular cavity which constitutes an upper pump chamber 139. This is the scavenger pump chamber as the pump is used in recirculating fuel system S. Body 123 has an external conical surface portion 141 at the bottom which engages the outer margin of the diaphragm 95 to clamp it against the conical diaphragm-seating surface 67 of the lower pump body 61. Body 123 is held in assembly on the lower pump body 61 by a sheet metal ring 143 surrounding the annular wall 65 of the lower pump body 61 and the .rimof body 123, this ring 141 having an upper portion 145 spun over on body 123 and a lower portion 147 spun under the body 61 to hold the parts together with sufiicient compression of the outer margin of the diaphragm for sealing thereof against surfaces 67 and 141. Thus, bodies 61 and 123 constitute a pump casing providing the two pump chambers 125 and 139 separated by the diaphragm 95.

The upper pump body 123 has an upwardly extending hollow central boss 151 and two bosses 153 and 155 at opposite sides of the central boss 151. Bosses 153 and 155 are cored to provide cylindrical recesses 157 and 159 extending up from pump chamber 139 and open at their lower ends to this chamber. Above recess 157 is an upper pump inlet passage 161 (the scavenger inlet passage as the pump is used in recirculating system S) in which is. fitted the inlet nipple 29. Extending tangentially from the upper part of recess 159 is a pump outlet passage 163 (the scavenger outlet passage as the pump is used in recirculating system S) in which is fitted the outlet nipple 33. Recess 157 contains an inlet check valve 165; recess 159 contains an outlet check valve 167. A coil compression spring 169 reacts from the upper end of hollow boss 151 downward against the top of head 191 to bias the latter downward. This is the spring previously referred to which acts. to return the rocker arm 47 in counterclockwise direction. Boss 151 has a central projection 171 extending downward from its top for centering the spring 169 and filling the space within the spring for increasing the volumetric efiiciency of the upper pump section 27.

The check valves 91, 93, 165 and 167, as shown, are all identical. Each comprises a circular valve seat 173 having a central hole 175 and a series of ports 177, such as arcuate slots, around the hole 175. Press-fitted in the hole 175 is a hollow stem 179 closed at its end in the hole, and having at its other end a mushroom head constituting a spring seat 181. A ring-shaped disk valve member 183, which may be made of a suitable fuel-resistant synthetic rubber for cushioned sealing, is slidable on the stem 179, and is biased toward engagement with the valve seat by a coil compression spring 185 surrounding the stem reacting from the spring seat 181. As to each of the four check valves, the valve seat 173 is press-fitted and positioned horizontally in the respective recess 79, 81, 157, 159, with the disk valve member 183 and stem 179 on the appropriate side for inward or outward opening of the valve member, as the case may be. Thus, the stems 179 of the valve91'for inlet passage recess 79 and the valve 167 for outlet passage recess 159 extend upward and the stems 179 of the valve 93 for routlet passage recess 81 and the valve 165 for inlet rpassage recess 157 extend downward.

In the operation of the dual diaphragm pump P, and upon each revolution of the cam 59, starting with the cam in the FIG. 2 position wherein its low point engages the push rod 57, the rocker arm 47 swings clockwise from its FIG. 2 position to its FIG. 5 position and then swings back from its FIG. 5 position toward its FIG. 2 position. The rocker arm is driven clockwise by the cam 59, counterclockwise by the spring 169 acting through the rod 127. With the rocker arm in the FIG. 2 position, its end which engages rod 127 is at the lower limit of its movement. Accordingly, rod 127 is at the lower limit of its vertical sliding movement, the head 101 is at the lower limit of its range of vertical movement, and the slack loop of the diaphragm is at the limit of its downward flexure. Under these circumstances, the l-ower pump chamber (the primary chamber) is fully contracted and the upper pump chamber 139 (the scavenger pump chamber) is 'fully expanded. The air chamber 111 is fully contracted.

As the end of the rocker arm 47 in engagement with rod 127 moves upward, it pushes rod 127 and head 101 upward against the downward bias or spring 169. Head 101 pulls the flat bottom portion of the looped free intermediate annular portion of the diaphragm upward. This expands the lower (primary) pump chamber 125 and efiect a suction stroke as regards the lower (primary) pump section 17 (inlet valve 91 opening up as the diaphragm is flexed upward and outlet valve 93 being held closed), and simultaneously contracts the upper (scavenger) pump chamber139 and effects a discharge stroke as regards the upper (scavenger) pump section 27 (outlet valve 167 opening up as the diaphragm is flexed upward and inlet valve being held closed). Accordingly, fuel is drawn from the tank 5 via line 21 into the primary chamber 125, and fuel is discharged from the scavenger chamber 139 via line 35 to the tank. As the head 191 is pushed upward by the rod 127, air chamber 111 expands. Air enters chamber 111 as it expands through the breather passage 133 to avoid development or a vacuum in chamber 111. In this respect, it will be observed that if a vacuum were developed in chamber 111, the force required to drive the diaphragm upward might be excessive, and oil might be sucked in from the crankcase. At the upper end of the stroke of rod 127, spring 169 is fully loaded.

As the end of the rocker arm in engagement with rod 127 completes its upward movement, the rod 127 and the head 101 reach the posit-ion shown in FIG. 5, the slack loop of the diaphragm then being bulged upward as appears in FIG. 5. This occurs when the high point of the cam engages the push rod from the cam position shown in FIG. 2). Then, as the cam completes a revolution, spring 169 becomes effective to drive the head 101 and the rod 127 downward. The head 101. thereupon pushes the slack loop of the diaphragm downward to contract the lower (primary) pump chamber 125 and effects a discharge stroke as regards the lower (primary) pump section 17 (outlet valve 93 opening up as the diaphragm flexes downward and inlet valve 91 being held closed) and simultaneously expands the ripper (scavenger) pump chamber 139 to effect a suction stroke as regards the upper (scavenger) pump section (inlet valve 165 opening up as the diaphragm flexed downward and outlet valve 167 being held closed). Accordingly, fuel is discharged from the primary chamber 125 to the curburetor C via line 25, overflow fuel is drawn from the carburetor via line 31 into the scavenger chamber 139. As the head 101 is pushed downward, air chamber 111 contracts. Air in chamber 111 is then exhausted via breather passage 133. In this respect, it will be observed that if chamber 111 were closed, the spring force required to drive the diaphragm downward might be excessive, since it would have to be suflicient to compress air in chamber 111.

The extent to which head 101 and the slack loop of diaphragm 95 are driven downward by the spring 169 depends primarily upon the back pressure in the primary chamber 125. If the back pressure is high (i.e., if flow of fuel through line 25 to the carburetor is relatively restricted), the downward movement of head 101 and the slack loop of the diaphragm and consequently the output of the pump will be restricted. Conversely, if the back pressure is low, the downward movement of head 101 and the slack loop will be greater and, if sufliciently low, the head 101 will move downward to its lower limit in which it appears in FIGS. 2 and 6. The back pressure is controlled at the carburetor, as may be ascertained by reference to the stated copending Johnson application. On strokes of the diaphragm less than full stroke, the rocker arm 47 idles as regards rod 127 for part of the rocker arm stroke, slapping being prevented by the leaf spring 53.

Referring to FIG. 7 of the drawings, there is again shown the frame 1 of an automotive vehicle having engine 3 at the front, but with a conventional float-type carburetor PC on the intake manifold 7 of the engine.

Carburetor PC is supplied with fuel from tank by a system including a single-acting pump P1 of this invention which is supplied through a line 21a and delivers through a line 25a. There is no return to the tank in this type of system.

FIG. 8 discloses in detail the single acting pump P1 of FIG. 7 which incorporates a modification of the invention. Prime numbers indicate parts of the structure of FIG. 8, which correspond with similar parts of the structure of FIG. 2, while the same numbers are used for identical parts. As shown in FIG. 8, pump P1 has a cupshaped pump body 61 corresponding to body 61 of pump P, but this body, instead of being on the outer end of a rocker arm housing, is integrally formed on one end of a tubular rod housing 201 with hub 69 of body 61' coaxial with the tubular housing 201. This end of housing 201 is referred to as its outer end. At its inner end, tubular housing 201 is reduced as indicated at 203 to fit in a counterbore 205 at the outer end of a hole 207 specially drilled in the wall 209 of the crankcase of engine 3'. The diaphragm-actuating rod of pump P1 differs from the rod 127 of pump P and is specially designated 127a because of its differences. It is considerably longer than rod 127, and extends through tubular housing 201 and out of the inner end of housing 201, being slidable in a bushing 211 in the housing. Packing as indicated at 213 may be provided on the rod 127a in the bushing. This is not subject to attack by fuel. Adjacent its outer end, rod 127a has a wide annular groove 215. A cap 217 is telescoped over the outer end of the rod 127a, having an inturned lip 219 received in the groove 215 to hold the cap on the rod while allowing it to slide relative to the rod. A spring 221 reacts from bushing 211 against a flange 223 on the cap to bias the cap in the direction away from the rod.

The housing 201 has shoulders 225 for engagement by a clamping fork 227 (see FIGS. 8 and 9) to hold the pump P1 on the wall 209. Fork 227 has holes such as indicated at 229 receiving screws 231 projecting from the wall 209 and is clamped in place by nuts 233 threaded on the screws. Screws 231 also accept nuts 235 for clamping a closure plate 237 over the customary rocker arm hole 239 in the crankcase wall, this hole 239 not being used when pump P1 is used. With the pump P1 so mounted on the engine, rod 127a is aligned with the push rod 57 which is actuated by the engine-driven earn 59, the outer end of the push rod 57 engaging the end of the spring cap 217.

In pump P1, a sheet metal cap 241 replaces the body 123 of pump P, and hence pump P1 has only the one pump chamber and does not have the upper valves and 167 of pump P. Cap 241, as shown in FIG. 8, has a V-shaped annular portion 243 for clamping the outer margin of the diaphragm 95 against the conical diaphragm-seating surface 67' of body 61', and is held in assembly with body 61 by having a skirt 245 surrounding the annular wall 65' of body 61, this skirt having a rim portion 247 spun over on the body 61'. Cap 241 also has a vent hole 249. Cap 241 constitutes an enclosure for the hat-shaped or cup-shaped head 101.

In other respects, pump P1 is the same as pump P. Nipple 19 thereof has fuel supply line 2111 connected thereto, and nipple 23 has fuel delivery line 25a connected thereto. In the operation of pump P1, and upon each revolution of cam 59, starting with the cam in the FIG. 8 position wherein its low point engages the push rod 57, the diaphragm-actuating rod 127a is driven outward away from its FIG. 8 position and returned toward its FIG. '8 position by spring 169. In the FIG. 8 position, the pump chamber 125 is fully contracted. Upon outward movement of the rod 127a, head 101 pulls the slack loop of diaphragm 95 outward to draw fuel into chamber 125. The rod 127a completes its outward movement when the high point of the cam engages the push rod from the cam position shown in FIG. 8). Then spring 169 becomes effective to drive the head 101 and the slack loop of the diaphragm inward to effect a pumping stroke. The extent to which the head and slack loop of the diaphragm are driven inward depends upon the back pressure in chamber 125, which is determined by the position of the float of the float valve in the carburetor PC. If the float valve is closed, the head and slack loop of the diaphragm will remain in outward position against the inward bias of spring 169 until the float valve opens. Under such circumstances, and under conditions where the head and slack loop are actuated through less than a full stroke, spring cap 217 prevents slapping.

It will be observed that the construction shown in FIG. 8 enables the diaphragm-actuating rod 127a to be arranged directly in line with'push rod 57, eliminating any necessity for a rocker arm, while still allowing compression spring 169 to be located on the outside of the diaphragm to provide for spring-powered pump discharge, and without any packing being required on rod 127a to seal the pump chamber 125. Also, with the in-line arrangement, pump P1 can be located off to one side and downward from the engine so as to be less subject to engine heat such as tends to cause vapor difficulties.

It is contemplated that the dual pump P may be utilized as a double-acting pump in a float carburetor fuel system. This may be accomplished by supplying fuel from the tank to the two pump inlets 19 and 29 and connecting the two pump outlets for delivering fuel to the carburetor, with a suitable by-pass arrangement to by-pass excessive delivery from chamber 139 of the pump around to chamber 125 of the pump on upward movement of rod 127 by the cam 59.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. A fuel pump for use on an internal combustion engine for pumping fuel to a carburetor for the engine, said engine having a push rod actuated thereby, said pump comprising a housing adapted for mounting at one end thereof on the engine in line with the push rod, a pump body on the other end of the housing, said housing having an opening therethorugh extending from its said one end to the body, a diaphragm having a hole therein secured to the body with the hole registering with said opening, the diaphragm being marginally sealed to the body and also sealed to the body around said opening by a tubular clamp element extending through the center hole in the diaphragm and secured in the opening in the body with a flange thereon engaging the diaphragm around its center hole, with an intermediate annular portion of the diaphragm free for flexure, thereby providing an annular pump chamber on one side of the diaphragm adapted to be expanded and contracted by the diaphragm, a head secured in sealed relation to said intermediate annular portion of the diaphragm on the other side of the diaphragm, and a pump ,rod slidable in said opening and extending through the hole in the diaphragm into engagement with the head, said pump rod extending through and being spaced from said tubular element to permit free reciprocatory motion of said rod without being interfered with by said tubular clamp element, said pump rod adapted to be aligned with and actuable by said push rod when the pump is mounted on the engine.

2. A fuel pump as defined in claim 1 including passage means formed in said housing, said passage means being communicated with an intermediate space formed between said head and said housing and atmosphere, thereby providing a breather passage for entry of air to, and escape of air from said intermediate space as said diaphragm is reciprocated.

3. A fuel pump for use in an internal combustion engine for pumping fuel to a carburetor for the engine, said engine having a push rod actuated thereby, said pump comprising a housing adapted for mounting at one end thereof on the engine in line with the push rod, a cup-shaped pump body having a central hub on the other end of and aligned with the housing, said housing having an opening therethrough extending from its said one end through the hub, a diaphragm having a center hole registering with the opening in the hub, the diaphragm having its inner margin around its center hole sealed to the hub around the opening in the hub and having its outer margin sealed to the wall of the cup-shaped body with an intermediate annular portion of the diaphragm between said hub and Wall constituting an annular slack loop free for flexure, thereby providing an annular pump chamber on the side of the diaphragm toward the body adapted to be expanded and contracted by said loop, said body having a valved inlet and a valved outlet for said chamber, a cup-shaped head having a rim portion secured in sealed relation to the loop on the other side of the diaphragm, and a rod extending slidably through the opening in the hub and the center hole in the diaphragm and engaging said head, said rod being adapted for reciprocation by said push rod to actuate the head thereby to actuate the diaphragm, and an enclosure on said cup-shaped body for the head and diaphragm, said enclosure clamping the outer margin of the diaphragm against the wall of the body, the inner margin of the diaphragm around the center hole therein being clamped against the end of the hub by a tubular clamp element being spaced from the said rod and secured in the opening in the hub, and a compression spring reacting from said enclosure against the head for driving the head and the intermediate annular portion of the diaphragm in the direction for contracting said annular pump chamber, said rod being adapted to move said head and the intermediate annular portion of the diaphragm in the opposite direction to expand said chamber and load said spring. 1

4. A fuel pump as defined in 'claim 3 including passage means formed in said body and terminating in said hub, said passage means being communicated with a source of air from atmosphere to provide a breather passage for entry of air to, and escape of air from an intermediate space formed between said head and said diaphragm as the latter is reciprocated.

References Cited by the Examiner UNITED STATES PATENTS 1,883,459 10/1932 Avigdor 103150 2,297,653 9/ 1942 Horton et al 103-152 2,367,055 1/1945 Rike et al. 15836.3 2,385,513 9/1945 Helvern et al. 15836.3 2,840,002 6/1958 Elder et al. 103-150 2,851,957 9/1958 Ragland 103-150 2,868,135 1/ 1959 Reinertson 103-450 2,904,876 9/ 1959 Edelen 103-150 FOREIGN PATENTS 720,745 12/ 1931 France. 44,169 11/ 1934 France.

1,247,788 10/ 1960 France.

348,108 1/ 1922 Germany.

137,679 1/ 1920 Great Britain.

734,294 7/ 1955 Great Britain.

MARK NEWMAN, Primary Examiner.

LAURENCE V. EFNER, JOSEPH H. BRANSON, JR.,

Examiners.

WARREN E. COLEMAN, DONLEY J. STOCKING,

H. W. MILTON, Assistant Examiners. 

1. A FUEL PUMP FOR USE ON AN INTERNAL COMBUSTION ENGINE FOR PUMPING FUEL TO CARBURETOR FOR THE ENGINE, SAID ENGINE HAVING A PUSH ROD ACTUATED THEREBY, SAID PUMP COMPRISING A HOUSING ADAPTED FOR MOUNTING AT ONE END THEREOF ON THE ENGINE IN LINE WITH THE PUSH ROD, A PUMP BODY ON THE OTHER END OF THE HOUSING, SAID HOUSING HAVING AN OPENING THERETHROUGH EXTENDING FROM ITS ONE END TO THE BODY, A DIAPHRAGM HAVING A HOLE THEREIN SECURED TO THE BODY WITH THE HOLE REGISTERING WITH SAID OPENING, THE DIAPHRAGM BEING MARGINALLY SEALED TO THE BODY AND ALSO SEALED TO THE BODY AROUND SAID OPENING BY A TUBULAR CLAMP ELEMEMT EXTENDING THROUGH THE CENTER HOLE IN THE DIAGPHRAGM AND SECURED IN THE OPENING IN THE BODY WITH A FLANGE THEREIN ENGAGING THE DIAPHRAGM AROUND ITS CENTER HOLE, WITH AN INTERMEDIATE ANNULAR PORION OF THE DIAPHRAGM FREE FOR FLEXURE, THEREBY PROVIDING AN ANNULAR PUMP CHAMBER ON ONE SIDE OF THE DIAPHRAGM ADAPTED TO BE EXPANDED AND CONTRACTED BY THE DIAPHRAGM, A HEAD SECURED IN SEALED RELATION TO SAID INTERMEDIATE ANNULAR PORTION OF THE DIAPHRAGM ON THE OTHER SIDE OF THE DIAPHRAGM, AND A PUMP ROD SLIDABLE IN SAID OPENING AND EXTENDING THROUGH THE HOLE IN THE DIAPHRAGM INTO ENGAGEMENT WITH THE HEAD, SAID PUMP ROD EXTENDING THROUGH AND BEING SPACED FROM SAID TUBULAR ELEMENT TO PERMIT FREE RECIPROCATORY MOTION OF SAID ROD WITHOUT BEING INTERFERED WITH BY SAID TUBULAR CLAMP ELEMENT, SAID PUMP ROD ADAPTED TO BE ALIGNED WITH AND ACTUATE BY SAID PUSH ROD WHEN THE PUMP IS MOUNTED ON THE ENGINE. 